Sang-Soo Kim

Screening of Some Crude Plant Extracts for Their Acaricidal and Insecticidal Efficacies

Abstract Methanol extracts from 28 samples of 22 plant species in 17 different plant families were tested at 10, 000 ppm for evaluating their insecticidal and acaricidal activities against Tetranychus urticae Koch, Aphis gossypii Glover, Myzus persicae Sulzer, Trialeurodes vaporariorum (Westwood), and Panonychus citri (McGregor). In a test with T. urticae, extracts from Albizzia coreana twig and Pyracantha angustifolia leaf possessed potent acaricidal activities. Reproduction of T. urticae for three days significantly decreased in the extract treatments of Gardenia jasminoides, Ficus carica, and Albizzia coreana twigs. Though slight repellent activities against T. urticae were obtained from extracts of Camellia japonica seed, G. jasminoides peel and fruits, Ligustrum japonicum leaves, A. coreana twig, and Machilus thunbergii leaves in 24 h after treatment, but tended to decrease in 72 h. Extracts of F. carica leaves and G. jasminoides fruits had potent insecticidal activities against M persicae and A. gossypii. Methanol extracts of F. carica leaves possessed insecticidal activity against T. vaporariorum. In a field test with P. citri, extracts from C. japonica seeds, A. coreana leaves, Ranunculus japonicus leaves and roots, an Houttuynia cordata leaves exhibited acaricidal activities.

Effects of Selected Pesticides on the Predatory Mite, Amblyseius cucumeris (Acari: Phytoseiidae)

Effects of field rates of selected pesticides to the predatory mite, Amblyseius cucumeris (Oudemans) (Acari: Phytoseiidae), were evaluated in laboratory bioassays. Five of the pesticides tested, ac...

Pheromone trap type and height for attracting of Riptortus clavatus (Thunberg) (Hemiptera: Alydidae) in soybean field.

This study was conducted to determine pheromone trap type and height in forecasting populations of R. clavatus in soybean fields using pheromone. The most effective pheromone trap type and height in forecasting populations of R. clavatus were fish trap and 60 cm above ground. Ratio of R. clavatus adults female and male in soybean field was 1.5 to 1 and Piezodorus hybneri was also attracted to the aggregation pheromone trap of R. clavatus. Attractiveness of two stink bug species caught on synthesis pheromone of R. clavatus was surveyed with imported production and synthesized production. Imported pheromone attracted only adult of R. clavatus, but synthesized pheromone attracted both adult of R. clavatus and P. hybneri. Change of population of R. clavatus was observed using pheromone trap and sweeping method in soybean field. Adults of R. clavatus occurred from early August and the population reached its peak in early September when pheromone trap was used. In case of sweeping method, its fluctuation pattern was similar to that of pheromone trap.

Status of the Occurrence of Insect Pests and Their Natural Enemies in Soybean Fields in Honam Province

This survey was conducted to illustrate insect pests and their natural enemies in soybean fields in Honam area. A total of 23 pest species in 13 families and 13 species of natural enemy were observed during 2002 to 2003. Delia platura, Medythia nigrobilineata, Spodoptera exigua and Aphis glycines occurred relatively with high population densities during the early growth stage of soybean. Dolycoris baccarum, Riptortus clavatus, Nezara antennata, Piezodorus hybneri and Halyomorpha halys began to occur between mid July to early August and lasted until the harvest time. Lepidopteran insect pests, Leguminivora glycinivorella, Pleuroptya ruralis, Scopula missaria, Macdunnoughia purissima and Spodoptera litura occurred significantly in late August in soybean field. Natural enemies of soybean insect pests observed in this survey were seven parasitoids, five predators, and an entomopahogenic fungus. Two egg parasitoid species for R. clavatus, two parasitoid species for P. ruralis, and five natural enemy species (including parasite, predator and entomopathogenic fungi) for either S. litura or A. glycines were identified, respectively. Among them two egg parasitoid species, Gryon japonicum and Ooenyrtus nezarae for R. clavatus, for and one parasitoid species for P. ruralis, that belong to Bethylidae, were new to Korea.

Biological Control of Thrips palmi (Thysanoptera: Thripidae) with Orius strigicollis (Hemiptera: Anthocoridae) on Cucumber in Plastic Houses in the Southern Region of Korea

Abstract Field evaluations were conducted to determine the efficacy of Orius strigicollis for biological control of Thrips palmi with different initial density in plastic houses. O. strigicollis released three times after 0, 5, 30, 100 thrips were inoculated per 30 cucumber plants. Three hundred and sixty predators were released in each plot. After inoculation of 5 T. palmi per 30 plants in each plot in plastic houses, T. palmi population increased rapidly with 16.3 individuals per plant in the fourth week, and O. strigicollis could not suppress T. palmi population because O. strigicollis population did not build up quickly. In the plot of 30 thrips inoculation, the density of O. strigicollis increased to 2.1 individuals per plant in the third week and 9.8 individuals per plant in the sixth week. The density of T. palmi increased to 33.8 individuals per plant in the sixth week. In the 100 thrips inoculation plot, the density of O. strigicollis increased to 9 individuals per plant in sixth week, which was similar to that in the 30 thrips inoculation plot. But the density of T. palmi increased rapidly from 2.9 to 384.7 individuals per plant in the sixth week. So, control of T. palmi by O. strigicollis did not appear. In autumn culture, in the 5 thrips inoculation plot, the density of O. strigicollis was so low that it could not suppress thrips density. In the 100 thrips inoculation plot, the density of T. palmi was so high that O. strigicollis could not suppress T. palmi density. In the 30 thrips inoculation plot, the density of O. strigicollis was 4.8 individuals per plant in the sixth week and the thrips population was suppressed. But O. strigicollis could not suppress the thrips population after sixth week because of low temperature and short photoperiod. These results indicate that control of T. palmi using O. strigicollis may be possible on cucumber in the spring culture.